Lens barrel unit

ABSTRACT

A lens barrel unit includes gyro sensors that detect vibration. The gyro sensors are disposed around a CCD mounting portion within a range over which the lens barrel unit is projected along the optical axis of a photographic optical system. This positional arrangement allows the lens barrel unit to be provided as a compact retractable unit, and ultimately achieves miniaturization of the camera.

The disclosure of the following priority application is hereinincorporated by reference:

-   Japanese Patent Application No. 2003-431889 filed Dec. 26, 2003

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a lens barrel unit that is built into acamera capable of executing blur correction to correct an image blurcaused by unsteady hand movement.

2. Description of the Related Art

A camera in which blur correction control is executed to correct imageblur caused by unsteady hand movement or the like normally includes avibration sensor that detects vibration in the camera. The blurcorrection control is executed by driving a blur correction opticalsystem or an image-capturing element based upon the results of thedetection provided by the vibration sensor.

Japanese Laid Open Patent Publication No. H 9-160107 discloses a camerawith a built-in lens barrel unit, which uses a non-interchangeable lens.In this camera, two vibration sensors used for the blur correctioncontrol are disposed in the grip of the camera, away from the lensbarrel unit, so as to provide the camera as a compact unit.

Extremely fine control is required during a blur correction operation.Accordingly, it is necessary to perform an integrated adjustment andinspection by adjusting the vibration sensor and the blur correctiondrive unit in conjunction with each other when assembling a camerahaving a blur correction mechanism.

However, if the vibration sensor is disposed at a distance from the lensbarrel unit, as in the camera described above, the adjustment andinspection of the blur correction mechanism cannot be performed unlessthe lens barrel unit is already mounted in the camera.

SUMMARY OF THE INVENTION

A lens barrel unit according to a first aspect of the present inventioncomprises a photographic optical system; a drive force generating unitthat generates a drive force with which the photographic optical systemis caused to move; a drive mechanism that moves the photographic opticalsystem with the drive force received from the drive force generatingunit; an image-capturing element mounting portion at which animage-capturing element that captures an image obtained through thephotographic optical system is mounted; and a vibration detection devicethat detects vibration and is disposed in an area surrounding theimage-capturing element mounting portion within a range in which thelens barrel unit is projected along an optical axis of the photographicoptical system.

The drive force generating unit generates the drive force so as to causethe photographic optical system to move along the optical axis; and thedrive force generating unit and the vibration detection device aredisposed at positions facing opposite each other over theimage-capturing element mounting portion.

It is preferable that the vibration detection device includes twovibration sensors; and the vibration sensors are both disposed in thearea surrounding the image-capturing element mounting portion within therange in which the lens barrel unit is projected along the optical axisof the photographic optical system. The two vibration sensors may bemounted on a sensor board constituted of a hard board; and the sensorboard may be fixed onto a member constituting the image-capturingelement mounting portion as an integrated part thereof. The twovibration sensors may also be mounted on a hard board which is disposedin a plane substantially perpendicular to the optical axis and in thearea surrounding the image-capturing element mounting portion within therange in which the lens barrel unit is projected along the optical axisof the photographic optical system.

The lens barrel unit according to the first aspect further comprises aterminal unit that achieves an electrical connection with an externaldevice, and at least one of an adjustment operation and an inspectionoperation related to a blur correction operation is executed based upondetection results provided by the vibration detection device with powersupply and control communication achieved via the terminal unit.

The lens barrel unit according to the first aspect may further comprisea retract motor that generates a drive force to reduce a length of thelens barrel unit.

A lens barrel unit according to a second aspect of the present inventioncomprises a photographic optical system that includes a blur correctionoptical system; a vibration detection device that is disposed in an areasurrounding an image-capturing element mounting portion at a positionwhich does not project out along a radial direction beyond an outermostperimeter of the lens barrel unit and detects vibration occurring alongtwo directions perpendicular to an optical axis of the photographicoptical system; and a blur correction drive unit that drives the blurcorrection optical system in correspondence to a detection valueprovided by the vibration detection device.

A camera according to a third aspect of the present invention comprisesa lens barrel unit according to claim 1 that is built in the camera.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 shows a vertical section of an area around the center of theoptical axis in a camera having a lens barrel unit achieved in anembodiment of the present invention;

FIG. 2 shows a horizontal section of the area around the center of theoptical axis in the camera shown in FIG. 1;

FIG. 3 is a perspective of the lens barrel unit, viewed from the sideindicated by the arrow A in FIG. 2;

FIG. 4 shows the lens barrel unit viewed from the side indicated by thearrow B in FIG. 2;

FIG. 5 shows the lens barrel unit in FIG. 4 without a blur correctionboard; and

FIG. 6 is a longitudinal sectional view schematically showing therelationship between the blur correction board and the gyro board.

DESCRIPTION OF THE PREFERRED EMBODIMENT

The following is an explanation of a lens barrel unit achieved in anembodiment of the present invention, given in reference to the drawings.

FIG. 1 is a vertical section of an area around the center of an opticalaxis in a camera having a lens barrel unit 2 achieved in the embodiment.FIG. 2 is a horizontal section of the area around the center of theoptical axis in the camera shown in FIG. 1. As shown in FIGS. 1 and 2,the camera uses a non-interchangeable lens with the lens barrel unit 2built therein. In a single lens reflex camera in which aninterchangeable lens is used, a vibration sensor used to detectvibration is mounted between, for instance, a photographic opticalsystem of the interchangeable lens and a mounting portion of theinterchangeable lens at a position outside the optical path so as not toblock the light flux.

In a camera with a non-interchangeable lens such as the camera achievedin the embodiment, the length of the lens barrel is usually reduced andthe lens is retracted when, for instance, the power is turned off so asto be handled as a more compact unit. Since the lens frame member movesby a significant extent along the optical axis when the lens retracts,it is difficult to dispose the vibration sensor around the optical pathas in a camera with an interchangeable lens, as described above.

Moreover, if the lens barrel and the vibration sensor are disposed awayfrom each other in order to achieve miniaturization of the camera, itwill be difficult to adjust and inspect the blur correction mechanismwith ease during the assembly process, which is bound to result in anincrease in production costs.

Accordingly, the positional arrangement of vibration sensors used in theembodiment to detect vibrations of the camera is improved so as toachieve miniaturization of the camera without leading to a costincrease.

As shown in FIGS. 1 and 2, the camera achieved in the embodimentincludes a camera main body 1, the lens barrel unit 2, a CCD 3, a flashlight emitting unit 4, an electronic viewfinder (EVF) 5, a monitor 6, amain condenser 7, a flash light emitter board 8, a battery 9, a cameracontrol board 10, a memory card unit 11, a blur correction board 12, agyro board 13, a focus motor 14, a zoom motor 15, a retract motor 15 b,a CCD mounting member 16, a photographic optical system L and the like.

The camera main body 1 is constituted of a cover member which forms theouter casing of the camera. The camera main body 1 is a member thatconstitutes the base of the entire camera, at which the various unitsmentioned above are mounted.

The lens barrel unit 2 includes the photographic optical system L, theblur correction board 12, the gyro board 13, the focus motor 14, thezoom motor 15, the retract motor 15 b, the CCD mounting member 16 andthe like. The photographic optical system L includes a lens L1, a blurcorrection lens L2 (blur correction optical system) and the like. As theblur correction lens L2 is driven by a blur correction drive unit 30 soas to move along a direction perpendicular to an optical axis 0, itengages in a blur correction operation for correcting an image blur.

The lens barrel unit 2, its components and the like are to be explainedlater.

The CCD 3 is an image-capturing element that captures an image formedthrough the photographic optical system L at its image-capturingsurface. The CCD 3 is locked to a CCD mounting portion 16 a (see FIG. 3)of the CCD mounting member 16.

The flash light emitting unit 4 is disposed atop the camera main body 1and includes a flash light emitter (not shown) that emits auxiliaryilluminating light during a photographing operation. The flash lightemitter, which is stored at a storage position when not in use, iseither automatically or manually popped up to an operating position asnecessary.

The electronic view finder (EVF) 5 is a display unit disposed furthertoward a photographer relative to the flash light emitting unit 4 at thetop of the camera. As the photographer looks into an eyepiece portion ofthe EVF 5, he is able to observe a subject image obtained via the CCD 3.

The monitor 6, which is disposed on the rear side (the surface facingtoward the photographer) of the camera, is a display unit constitutedwith a liquid crystal display device larger than the EVF 5. At themonitor 6, the subject image obtained via the CCD 3 and information suchas the details of the settings selected for the camera are displayed.The monitor 6 can be oriented in any direction on a fulcrum set at ahinge portion 6 a thereof.

The main condenser 7 is a condenser that stores the energy required toemit light in the flash light emitting unit 4. As shown in FIG. 2, withthe side of the camera held by the right-hand of the photographerholding the camera sideways referred to as the right-hand side and theopposite side of the camera referred to as the left-hand side, the maincondenser 7 is disposed further on the right-hand side relative to thelens barrel unit 2 and further toward the subject relative to the flashlight emitter board 8.

The flash light emitter board 8, which is connected with the flash lightemitting unit 4, the main condenser 7, the camera control board 10 andthe like, is a board at which circuits required for flash light emissionare formed. The flash light emitter board 8 is disposed at a positionwhich is substantially the same as the position of the main condenser 7but is further toward the photographer relative to the main condenser 7.

The battery 9, from which power is supplied to the camera, is disposedinside the grip by which the right-hand of the photographer holds thecamera.

The camera control board 10 is a board at which a circuit that controlsthe main operations of the camera is formed and is fixed to the CCDmounting member 16.

The memory card unit 11 reads/writes data in a memory card used as astorage medium in which photographic image data are stored and is fixedto the camera control board 10.

The focus motor 14 is a drive force generating unit that generates adrive force with which a focus lens (not shown) inside the photographicoptical system L is driven via a drive mechanism constituted with a lensframe (not shown) and the like. The focus motor 14 is disposed above theCCD mounting portion 16 a. The focus lens is caused to move along theoptical axis 0 by the drive force imparted by the focus motor 14.

The zoom motor 15 is a drive force generating unit that generates adrive force for adjusting the focal length of the photographic opticalsystem L via a drive mechanism constituted with a zoom gearbox 15 a (seeFIG. 3), the lens frame (not shown) and the like. A lens which is partof the photographic optical system L and adjusts the focal length iscaused to move along the optical axis O by the drive force imparted fromthe zoom motor 15. The zoom motor 15 and the zoom gearbox 15 a aredisposed on the left-hand side of the CCD mounting portion 16 a.

The retract motor 15 b generates a drive force for retracting with whichthe length of the lens barrel unit 2 is reduced so as to achieveminiaturization of the camera. It is to be noted that the zoom motor 15may be used as the retract motor 15 b.

It is to be noted that the focus motor 14, the zoom motor 15 and theretract motor 15 b are electrically connected with the camera controlboard 10 through wiring (not shown).

Next, the lens barrel unit 2 is explained in further detail.

FIG. 3 is a perspective of the lens barrel unit 2, viewed from the sideindicated by the arrow A in FIG. 2.

FIG. 4 shows the lens barrel unit 2, viewed from the side indicated bythe arrow B in FIG. 2.

The CCD mounting member 16 includes the CCD mounting portion 16 a, whichis an image-capturing element mounting portion, and screw holes at whichthe blur correction board 12, the gyro board 13 and the like are fixed,are formed at the CCD mounting member 16. Excluding its CCD mountingportion 16 a, i.e., excluding the portion around the optical axis 0, theCCD mounting member 16 adopts a shape that allows it to cover a sectionof the lens barrel unit 2.

The blur correction board 12 is a hard board at which a drive circuitengaged to drive a VCM (voice coil motor) of the blur correction driveunit 30 and the like are formed. The VCM causes the blur correction lensL2 to move along a direction perpendicular to the optical axis O. Theblur correction board 12, which is disposed in a substantially L shapeso as to enclose the lower portion and the right-hand side of the CCDmounting portion 16 a of the CCD mounting member 16, is locked onto theCCD mounting member 16 with screws 21 disposed at three positions. Theblur correction drive unit 30 is electrically connected with the blurcorrection board 12 via wiring (not shown).

A terminal unit 12 a that electrically connects with an externalinspection device is provided at the blur correction board 12. Whenadjusting and inspecting the lens barrel unit 2, it is connected withthe external inspection device through the terminal unit 12 a to achievepower supply and control communication, and as a result, an adjustmentoperation and an inspection operation related to the blur correctionoperation can be executed based upon the results of detection providedby gyro sensors 17 and 18 to be detailed later. A terminal unit 12 b iselectrically connected with the camera control board 10 via wiring (notshown)

FIG. 5 shows the lens barrel unit 2 in FIG. 4 with no blur correctionboard 12 installed therein.

FIG. 6 is a longitudinal sectional view schematically showing therelationship between the blur correction board 12 and the gyro board 13.The blur correction board 12 and the gyro board 13 are electricallyconnected with each other through wiring (not shown).

The gyro board 13 having the gyro sensors 17 and 18 mounted thereupon isa sensor board constituted with a hard board. The 13 is disposed on theright-hand side relative to the CCD mounting portion 16 a of the CCDmounting member 16 further toward the subject relative to the blurcorrection board 12. In other words, the gyro board 13 is disposed in aplane substantially perpendicular to the optical axis O around the CCDmounting portion 16 a within a range over which the lens barrel unit 2is projected along the optical axis O of the photographic optical systemL. The gyro board 13 is fixed to the CCD mounting member 16 so as toform an integrated part thereof through screws 20 disposed at threepositions.

The gyro sensors 17 and 18 are vibration sensors used to detectvibrations of the camera and are mounted at the surface of the gyroboard 13 facing toward the subject. The gyro sensors 17 and 18 are thesame type of vibration detector and are respectively disposed along thehorizontal direction and the vertical direction in FIG. 5. The gyrosensors 17 and 18 respectively detect vibrations manifesting along thehorizontal direction and the vertical direction in FIG. 5, runningperpendicular to each other. The detection values provided by the gyrosensors 17 and 18 are output to the drive circuit formed on the blurcorrection board 12. The blur correction drive unit 30 drives the blurcorrection lens L2 along the direction perpendicular to the optical axisO in correspondence to the detection values provided by the gyro sensors17 and 18 and thus, the blur correction operation is executed.

As shown in FIG. 5, the gyro sensors 17 and 18 are disposed around theCCD mounting portion 16 a within the range R over which the lens barrelunit 2 is projected along the optical axis O of the photographic opticalsystem L. This range R matches the outer perimeter of the lens barrelunit 2. For this reason, the gyro sensors 17 and 18 can be regarded tobe disposed at positions at which they do not project out along theradial direction beyond the outermost perimeter of the lens barrel unit2. This positional arrangement allows the lens barrel unit 2 to beprovided as a compact and retractable lens barrel unit by effectivelyutilizing the available space around the CCD 3.

The gyro sensors 17 and 18 are disposed at positions facing opposite thezoom motor 15 over the CCD mounting portion 16 a. Since this positionalarrangement creates a significant distance from the gyro motors 17 and18 to the zoom motor 15, the vibration occurring when the zoom motor 15is being driven is not allowed to be transmitted to the gyro sensors 17and 18 readily.

If the zoom motor 15 was disposed near the gyro sensors 17 and 18, onthe other hand, the vibration occurring as the zoom motor 15 is drivenwould be picked up at the gyro sensors 17 and 18, which may lead to anerroneous operation in the blur correction control. However, since thegyro sensors 17 and 18 are disposed over a considerable distance fromthe zoom motor 15 in the embodiment, such erroneous operation can beavoided.

It is to be noted that the focus motor 14 is disposed at a positioncloser to the gyro sensors 17 and 18 compared to the zoom motor 15.However, since the extent of vibration occurring at the focus motor 14is relatively small compared to the extent of vibration occurring at thezoom motor 15, the likelihood of an erroneous operation is not high.However, it is desirable that the focus motor assume a position similarto that of the zoom motor 15 if the extent of vibration occurring at thefocus motor is great.

Since the gyro sensors 17 and 18 are disposed at the lens barrel unit 2,the adjustment and inspection operations related to the blur correctionoperation can be executed for the lens barrel unit 2 by itself, insteadof on the finished camera product after the assembly process.

The focus motor 14 and the zoom motor 15 are both disposed within therange R over which the lens barrel unit 2 is projected along the opticalaxis O of the photographic optical system L, as are the gyro sensors 17and 18. By disposing the relatively large members such as the focusmotor 14, the zoom motor 15 and the gyro sensors 17 and 18 in theavailable space around the CCD 3 as described above, the lens barrelunit 2 can be provided as a more compact unit and thus, miniaturizationof the overall camera is achieved.

In the embodiment described above, the gyro sensors 17 and 18 are usedas a vibration detection device. However, the present invention is notlimited to this example, and it may be adopted in conjunction withanother type of angular speed sensors capable of detecting vibrationsmanifesting along two directions perpendicular to the optical axis O.

(Example of Variation)

The present invention is not limited to the example presented in theexplanation of the embodiment above, and it allows for various changesand modifications and such changes and modifications equally fall intothe scope of the present invention.

The present invention is adopted in the lens barrel unit 2 that executesthe blur correction operation by moving the blur correction lens L2 inthe embodiment described above. However, the present invention is notlimited to this example and it may be adopted in a lens barrel unit thatexecutes blur correction by moving, for instance, the image-capturingelement.

The following is a summary of the lens barrel unit achieved in theembodiment of the present invention.

-   (1) The vibration sensors 17 and 18 used to detect vibrations are    disposed around the image-capturing element mounting portion 16 a    within the range R over which the lens barrel unit 2 is projected    along the optical axis O of the photographic optical system 1. Thus,    the available space around the image-capturing element 3 can be    effectively utilized to provide a compact and retractable lens    barrel unit 2.-   (2) The drive force generating unit 15 that imparts the drive force    with which the photographic optical system L is caused to move along    the optical axis O and the vibration sensors 17 and 18 are disposed    at positions facing opposite each other over the image-capturing    element mounting portion 16 a. This positional arrangement ensures    that the vibration generated as the drive force generating unit 15    is driven is not allowed to be transmitted to the vibration sensors    17 and 18 readily.-   (3) Both of the vibration sensors 17 and 18 are disposed around the    image-capturing element mounting portion 16 a within the range R    over which the lens barrel unit 2 is projected along the optical    axis O of the photographic optical system L. Thus, the lens barrel    unit 2 can be provided as a compact unit.-   (4) The vibration sensors 17 and 18 are mounted at the sensor board    13 constituted with a hard board, and the sensor board 13 is locked    to the member 16 that includes therein the image-capturing element    mounting portion 16 a as an integrated part thereof. Thus, the    vibration sensors 17 and 18 fixed to the lens barrel unit 2 enable    the adjustment operation and/or the inspection operation related to    the blur correction operation to be executed on the lens barrel unit    2 by itself with a high degree of accuracy.-   (5) The lens barrel unit 2 includes the terminal unit 12 a through    which an electrical connection with an external device is achieved.    With the power supply and the control communication achieved via the    terminal unit 12 a, the adjustment operation and/or an inspection    operation related to the blur correction operation can be executed    based upon the results of the detection obtained by the vibration    sensors 17 and 18. As a result, it becomes easier to handle the lens    barrel unit 2 during the manufacturing process and, at the same    time, the manufacturing costs can be reduced since any problem    related to the blur correction mechanism can be spotted before all    the components are assembled into a finished camera product.

The above described embodiments are examples and various modificationscan be made without departing from the spirit and scope of theinvention.

1. A lens barrel unit, comprising: a photographic optical system; adrive force generating unit that generates a drive force with which thephotographic optical system is caused to move; a drive mechanism thatmoves the photographic optical system with the drive force received fromthe drive force generating unit; an image-capturing element mountingportion at which an image-capturing element that captures an imageobtained through the photographic optical system is mounted; and avibration detection device that detects vibration and is disposed in anarea surrounding the image-capturing element mounting portion within arange in which the lens barrel unit is projected along an optical axisof the photographic optical system.
 2. A lens barrel unit according toclaim 1, wherein: the drive force generating unit generates the driveforce so as to cause the photographic optical system to move along theoptical axis; and the drive force generating unit and the vibrationdetection device are disposed at positions facing opposite each otherover the image-capturing element mounting portion.
 3. A lens barrel unitaccording to claim 1, wherein: the vibration detection device includestwo vibration sensors; and the vibration sensors are both disposed inthe area surrounding the image-capturing element mounting portion withinthe range in which the lens barrel unit is projected along the opticalaxis of the photographic optical system.
 4. A lens barrel unit accordingto claim 3, wherein: the two vibration sensors are mounted on a sensorboard constituted of a hard board; and the sensor board is fixed onto amember constituting the image-capturing element mounting portion as anintegrated part thereof.
 5. A lens barrel unit according to claim 1,further comprising: a terminal unit that achieves an electricalconnection with an external device, wherein: at least one of anadjustment operation and an inspection operation related to a blurcorrection operation is executed based upon detection results providedby the vibration detection device with power supply and controlcommunication achieved via the terminal unit.
 6. A lens barrel unitaccording to claim 2, wherein: the vibration detection device includestwo vibration sensors; and the vibration sensors are both disposed inthe area surrounding the image-capturing element mounting portion withinthe range in which the lens barrel unit is projected along the opticalaxis of the photographic optical system.
 7. A lens barrel unit accordingto claim 6, wherein: the two vibration sensors are mounted on a hardboard which is disposed in a plane substantially perpendicular to theoptical axis and in the area surrounding the image-capturing elementmounting portion within the range in which the lens barrel unit isprojected along the optical axis of the photographic optical system. 8.A lens barrel unit according to claim 1, further comprising: a retractmotor that generates a drive force to reduce a length of the lens barrelunit.
 9. A lens barrel unit, comprising: a photographic optical systemthat includes a blur correction optical system; a vibration detectiondevice that is disposed in an area surrounding an image-capturingelement mounting portion at a position which does not project out alonga radial direction beyond an outermost perimeter of the lens barrel unitand detects vibration occurring along two directions perpendicular to anoptical axis of the photographic optical system; and a blur correctiondrive unit that drives the blur correction optical system incorrespondence to a detection value provided by the vibration detectiondevice.
 10. A camera comprising: a lens barrel unit according to claim 1that is built in the camera.